The Glassmen Drum and Bugle Corps was a World Classdrum and bugle corps based out of Toledo, Ohio and was a sixteen time Drum Corps International (DCI) World Championship Finalist.

Richard "Dick" Ford and Jack Schnapp founded the corps as the Maumee SunsIn 1961, sponsored by American Legion Post 320 of Maumee, a suburb on the south side of Toledo. The unit was a parade corps before entering field competition in 1964. The corps acquired the co-sponsorship of the Toledo Optomists International club in 1967 and changed the corps name to the Glass City Optomists, which also paid tribute to Toledo's heritage as a leading glass manufacturing center. The "Glass Capital of the World" was more fully recognized when the corps' name was changed to the Glassmen in 1971.

The Glassmen first entered Drum Corps International (DCI) competitions in 1975, placing 5th of 19 corps in the Class A championships in Philadelphia before going inactive for the next four seasons. The Glassmen returned to the field in 1980 as a Class A corps, but by DCI Finals in Birmingham, Alabama the corps had moved up to Open Class, where it finished 42nd of 44 corps.

The Glassmen began competing in Drum Corps Midwest (DCM) shows In 1982 and became a member of the circuit the following year, placing 4th of 24 corps at the DCM Championships in DeKalb, Illinois. The '82 corps also placed 24th of 51 corps at DCI in Miami, Florida, earning DCI Associate membership. The following year, though, the corps dropped to 28th place and to 39th in 1985.

Following the 1985 season, Dan Acheson, the current executive director and CEO of DCI, was named executive director of the Glassmen. Under Acheson's leadership, each year from 1985 through 1995, the Glassmen moved up in the DCI standings. The corps regained DCI membership in 1988. It made DCI semifinals for the first time in 1991, and earned a spot in the DCI Top Twelve Finals for the first time in 1993. The corps had been a DCI Finalist for three straight years when Acheson was elected chairman of the board of DCI in 1995 and later that year was appointed to his current position.

After Acheson's departure, the Glassmen fell to 13th place and missed DCI Finals in 1996, only to return the following six seasons under new Executive Director Brian Hickman. The corps placed as high as 5th in 1998, '99, and 2001. After dropping from Finals again with a 14th place finish in 2003, the Glassmen returned for another seven-year Finals run from 2004 through 2010.

In 2004 and 2008, the Glassmen performed Respeghi's “Pines of Rome” in concert with the Toledo Symphony Orchestra, They performed Tchaikovsky's “1812 Overture” with the orchestra in 2006. In 2012 the orchestra and corps presented both works.

With another 13th place finish in 2011, the corps,along with many other non-profit organizations, began to fall victim to the difficult financial times of the faltering national economy during the "Great Recesssion." After slipping from 13th in 2011 to 14th in 2012, the organization was deep in debt and had no recourse but to sell off its assets to settle some of the debt load, but after a Federal Bankruptcy Court ruling in 2014 the corps became defunct.

In 2016, the Glassmen Alumni Association tried to restart the organization with a Winter Guard International unit, but met with no success, and the association also went inactive.